The user of an appliance that uses water often wishes to alter the properties of the water he or she uses to make it suitable for the purpose of the appliance. For example, the user of a washing machine generally wishes to treat laundry with antimicrobial treatment. In response to such needs, various proposals have been made, of which examples are disclosed in the publications listed below. Specifically, Publication 1 discloses an electric washing machine equipped with an ion generator that generates metal ions, such as silver or copper ions, that exert a sterilizing effect. Publication 2 discloses a washing machine that sterilizes washing fluid by applying an electric field thereto. Publication 3 discloses a washing machine furnished with a silver ion adding unit that adds silver ions to washing fluid. Publication 4 discloses a washing machine that performs washing and rinsing by using electrolyzed water obtained through electrolysis of water. Washing machines that administer antimicrobial treatment by using silver ions have already been commercially available.    Publication 1: Japanese Utility Model Application No. H5-74487 (p. 1, FIG. 1)    Publication 2: Japanese Patent Application Laid-Open No. 2000-93691 (p. 2, FIG. 1)    Publication 3: Japanese Patent Application Laid-Open No. 2001-276484 (p. 2, FIG. 1)    Publication 4: Japanese Patent Application Laid-Open No. 2003-24692 (pp. 3-6, FIGS. 8, 10, 12, and 17)